Document redaction and reconciliation

ABSTRACT

An example operation may include one or more of splitting, by a document server, a document provided by a document owner node into a plurality of segments to be stored on a ledger of a blockchain, detecting, by the document server, a change to the document made by an authorized participant node, updating, by the document server, a segment of the plurality of segments stored on the ledger based on the change to the document, collecting, by the document server, votes on the change to the document from a plurality of participant nodes, and committing the updated segment to the blockchain based on the votes.

TECHNICAL FIELD

This application generally relates to a database storage system, andmore particularly, to redaction and reconciliation.

BACKGROUND

A centralized database stores and maintains data in a single database(e.g., a database server) at one location. This location is often acentral computer, for example, a desktop central processing unit (CPU),a server CPU, or a mainframe computer. Information stored on acentralized database is typically accessible from multiple differentpoints. Multiple users or client workstations can work simultaneously onthe centralized database, for example, based on a client/serverconfiguration. A centralized database is easy to manage, maintain, andcontrol, especially for purposes of security because of its singlelocation. Within a centralized database, data redundancy is minimized asa single storing place of all data also implies that a given set of dataonly has one primary record.

However, a centralized database suffers from significant drawbacks. Forexample, a centralized database has a single point of failure. Inparticular, if there are no fault-tolerance considerations and failuresoccur (for example, a hardware, a firmware, and/or a software failure),all data within the database is lost and work of all users isinterrupted. In addition, centralized databases are highly dependent onnetwork connectivity. As a result, the slower the connection, the amountof time needed for each database access is increased. Another drawbackis the occurrence of bottlenecks when a centralized database experienceshigh traffic due to a single location. Furthermore, a centralizeddatabase provides limited access to data because only one copy of thedata is maintained by the database. As a result, multiple devices cannotaccess the same piece of data at the same time without creatingsignificant problems or risk overwriting stored data. Furthermore,because a database storage system has minimal to no data redundancy,data that is unexpectedly lost is very difficult to retrieve other thanthrough manual operation from back-up storage.

As such, what is needed is a blockchain-based solution that overcomesthese drawbacks and limitations. Blockchains may be used for securedocument sharing. Sometimes just portions of a document need to beshared securely for edits or review, while other parts of that documentmust remain classified because they contain sensitive information.Furthermore, sometimes portions of a shared document may need to beredacted. For example, there are regulations such as HIPPA, GDPR, PCI,where certain information such as social security numbers, credit cardnumbers and other personally identifiable data may need to be redactedfor compliance with standards. This complicates daily businesstransactions, because it restricts the exchange of documents. Forexample, the electronic document may contain PHI (personal health info)and may need to be send to a contracting vendor to extract billing codes(or other processing). The organization may not want to reveal the PHIto the contractor. Thus, a redacted version of the documents may beshared to fix/annotate billing codes without having PHI revealed.

While existing solutions may create a version of the original documentfor sharing, the changes to the derived document may not be easilyreconciled into the original document. Existing solutions often applyencryption of the file content as an after-thought or an additionalsecurity step(s), which leaves the files vulnerable to human error. Theencryption is built-in as part of a blockchain design. Also, in ablockchain network, only encrypted content is stored.

Accordingly, it is desired to have a blockchain-based solution forredaction and reconciliation of documents.

SUMMARY

One example embodiment provides a system that includes a processor andmemory, wherein the processor is configured to perform one or more ofreceive a document from a document owner node, the document containsrestricted access segments, split the document into a plurality ofledger entries to be stored on a blockchain, update a ledger entry ofthe plurality of the ledger entries based on a proposed change to thedocument made by an authorized participant node, commit the ledger entryto the blockchain based on votes collected from a plurality ofparticipant nodes, and send a notification to a set of participatingnodes of the plurality of the participant nodes authorized to view thedocument.

Another example embodiment provides a system that includes a processorand memory, wherein the processor is configured to perform one or moreof split a document provided by a document owner node into a pluralityof segments to be stored on a ledger of a blockchain, detect a change tothe document made by an authorized participant node, update a segment ofthe plurality of segments stored on the ledger based on the change tothe document, collect votes on the change to the document from aplurality of participant nodes, and commit the updated segment to theblockchain based on the votes.

Another example embodiment provides a method that includes one or moreof receiving, by a document server, a document from a document ownernode, the document contains restricted access segments, splitting, bythe document server, the document into a plurality of ledger entries tobe stored on a blockchain, updating, by the document server, a ledgerentry of the plurality of the ledger entries based on a proposed changeto the document made by an authorized participant node, committing, bythe document server, the ledger entry to the blockchain based on votescollected from a plurality of participant nodes, and sending anotification to a set of participating nodes of the plurality of theparticipant nodes authorized to view the document.

Another example embodiment provides a method that includes one or moreof splitting, by a document server, a document provided by a documentowner node into a plurality of segments to be stored on a ledger of ablockchain, detecting, by the document server, a change to the documentmade by an authorized participant node, updating, by the documentserver, a segment of the plurality of segments stored on the ledgerbased on the change to the document, collecting, by the document server,votes on the change to the document from a plurality of participantnodes, and committing the updated segment to the blockchain based on thevotes.

A further example embodiment provides a non-transitory computer readablemedium comprising instructions, that when read by a processor, cause theprocessor to perform one or more of receiving a document from a documentowner node, the document contains restricted access segments, splittingthe document into a plurality of ledger entries to be stored on ablockchain, updating a ledger entry of the plurality of the ledgerentries based on a proposed change to the document made by an authorizedparticipant node, committing the ledger entry to the blockchain based onvotes collected from a plurality of participant nodes, and sending anotification to a set of participating nodes of the plurality of theparticipant nodes authorized to view the document.

A further example embodiment provides a non-transitory computer readablemedium comprising instructions, that when read by a processor, cause theprocessor to perform one or more of splitting a document provided by adocument owner node into a plurality of segments to be stored on aledger of a blockchain, detecting a change to the document made by anauthorized participant node, updating a segment of the plurality ofsegments stored on the ledger based on the change to the document,collecting votes on the change to the document from a plurality ofparticipant nodes, and committing the updated segment to the blockchainbased on the votes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a network diagram of a system including a database,according to example embodiments.

FIG. 1B illustrates a network diagram of a system including a database,according to example embodiments.

FIG. 2A illustrates an example blockchain architecture configuration,according to example embodiments.

FIG. 2B illustrates a blockchain transactional flow, according toexample embodiments.

FIG. 3A illustrates a permissioned network, according to exampleembodiments.

FIG. 3B illustrates another permissioned network, according to exampleembodiments.

FIG. 4A illustrates a flow diagram, according to example embodiments.

FIG. 4B illustrates a further flow diagram, according to exampleembodiments.

FIG. 4C illustrates a flow diagram, according to example embodiments.

FIG. 4D illustrates a further flow diagram, according to exampleembodiments.

FIG. 5A illustrates an example system configured to perform one or moreoperations described herein, according to example embodiments.

FIG. 5B illustrates another example system configured to perform one ormore operations described herein, according to example embodiments.

FIG. 5C illustrates a further example system configured to utilize asmart contract, according to example embodiments.

FIG. 5D illustrates yet another example system configured to utilize ablockchain, according to example embodiments.

FIG. 6A illustrates a process for a new block being added to adistributed ledger, according to example embodiments.

FIG. 6B illustrates contents of a new data block, according to exampleembodiments.

FIG. 6C illustrates a blockchain for digital content, according toexample embodiments.

FIG. 6D illustrates a block which may represent the structure of blocksin the blockchain, according to example embodiments.

FIG. 7 illustrates an example system that supports one or more of theexample embodiments.

DETAILED DESCRIPTION

It will be readily understood that the instant components, as generallydescribed and illustrated in the figures herein, may be arranged anddesigned in a wide variety of different configurations. Thus, thefollowing detailed description of the embodiments of at least one of amethod, apparatus, non-transitory computer readable medium and system,as represented in the attached figures, is not intended to limit thescope of the application as claimed but is merely representative ofselected embodiments.

The instant features, structures, or characteristics as describedthroughout this specification may be combined or removed in any suitablemanner in one or more embodiments. For example, the usage of the phrases“example embodiments”, “some embodiments”, or other similar language,throughout this specification refers to the fact that a particularfeature, structure, or characteristic described in connection with theembodiment may be included in at least one embodiment. Thus, appearancesof the phrases “example embodiments”, “in some embodiments”, “in otherembodiments”, or other similar language, throughout this specificationdo not necessarily all refer to the same group of embodiments, and thedescribed features, structures, or characteristics may be combined orremoved in any suitable manner in one or more embodiments.

In addition, while the term “message” may have been used in thedescription of embodiments, the application may be applied to many typesof networks and data. Furthermore, while certain types of connections,messages, and signaling may be depicted in exemplary embodiments, theapplication is not limited to a certain type of connection, message, andsignaling.

Example embodiments provide methods, systems, components, non-transitorycomputer readable media, devices, and/or networks, which provide forredaction and reconciliation of a document.

In one embodiment the application utilizes a decentralized database(such as a blockchain) that is a distributed storage system, whichincludes multiple nodes that communicate with each other. Thedecentralized database includes an append-only immutable data structureresembling a distributed ledger capable of maintaining records betweenmutually untrusted parties. The untrusted parties are referred to hereinas peers or peer nodes. Each peer maintains a copy of the databaserecords and no single peer can modify the database records without aconsensus being reached among the distributed peers. For example, thepeers may execute a consensus protocol to validate blockchain storagetransactions, group the storage transactions into blocks, and build ahash chain over the blocks. This process forms the ledger by orderingthe storage transactions, as is necessary, for consistency. In variousembodiments, a permissioned and/or a permissionless blockchain can beused. In a public or permission-less blockchain, anyone can participatewithout a specific identity. Public blockchains often involve nativecrypto-currency and use consensus based on various protocols such asProof of Work (PoW). On the other hand, a permissioned blockchaindatabase provides secure interactions among a group of entities whichshare a common goal but which do not fully trust one another, such asbusinesses that exchange funds, goods, information, and the like.

This application can utilize a blockchain that operates arbitrary,programmable logic, tailored to a decentralized storage scheme andreferred to as “smart contracts” or “chaincodes.” In some cases,specialized chaincodes may exist for management functions and parameterswhich are referred to as system chaincode. The application can furtherutilize smart contracts that are trusted distributed applications whichleverage tamper-proof properties of the blockchain database and anunderlying agreement between nodes, which is referred to as anendorsement or endorsement policy. Blockchain transactions associatedwith this application can be “endorsed” before being committed to theblockchain while transactions, which are not endorsed, are disregarded.An endorsement policy allows chaincode to specify endorsers for atransaction in the form of a set of peer nodes that are necessary forendorsement. When a client sends the transaction to the peers specifiedin the endorsement policy, the transaction is executed to validate thetransaction. After validation, the transactions enter an ordering phasein which a consensus protocol is used to produce an ordered sequence ofendorsed transactions grouped into blocks.

This application can utilize nodes that are the communication entitiesof the blockchain system. A “node” may perform a logical function in thesense that multiple nodes of different types can run on the samephysical server. Nodes are grouped in trust domains and are associatedwith logical entities that control them in various ways. Nodes mayinclude different types, such as a client or submitting-client nodewhich submits a transaction-invocation to an endorser (e.g., peer), andbroadcasts transaction-proposals to an ordering service (e.g., orderingnode). Another type of node is a peer node which can receive clientsubmitted transactions, commit the transactions and maintain a state anda copy of the ledger of blockchain transactions. Peers can also have therole of an endorser, although it is not a requirement. Anordering-service-node or orderer is a node running the communicationservice for all nodes, and which implements a delivery guarantee, suchas a broadcast to each of the peer nodes in the system when committingtransactions and modifying a world state of the blockchain, which isanother name for the initial blockchain transaction which normallyincludes control and setup information.

This application can utilize a ledger that is a sequenced,tamper-resistant record of all state transitions of a blockchain. Statetransitions may result from chaincode invocations (i.e., transactions)submitted by participating parties (e.g., client nodes, ordering nodes,endorser nodes, peer nodes, etc.). Each participating party (such as apeer node) can maintain a copy of the ledger. A transaction may resultin a set of asset key-value pairs being committed to the ledger as oneor more operands, such as creates, updates, deletes, and the like. Theledger includes a blockchain (also referred to as a chain) which is usedto store an immutable, sequenced record in blocks. The ledger alsoincludes a state database which maintains a current state of theblockchain.

This application can utilize a chain that is a transaction log which isstructured as hash-linked blocks, and each block contains a sequence ofN transactions where N is equal to or greater than one. The block headerincludes a hash of the block's transactions, as well as a hash of theprior block's header. In this way, all transactions on the ledger may besequenced and cryptographically linked together. Accordingly, it is notpossible to tamper with the ledger data without breaking the hash links.A hash of a most recently added blockchain block represents everytransaction on the chain that has come before it, making it possible toensure that all peer nodes are in a consistent and trusted state. Thechain may be stored on a peer node file system (i.e., local, attachedstorage, cloud, etc.), efficiently supporting the append-only nature ofthe blockchain workload.

The current state of the immutable ledger represents the latest valuesfor all keys that are included in the chain transaction log. Since thecurrent state represents the latest key values known to a channel, it issometimes referred to as a world state. Chaincode invocations executetransactions against the current state data of the ledger. To make thesechaincode interactions efficient, the latest values of the keys may bestored in a state database. The state database may be simply an indexedview into the chain's transaction log, it can therefore be regeneratedfrom the chain at any time. The state database may automatically berecovered (or generated if needed) upon peer node startup, and beforetransactions are accepted.

Some benefits of the instant solutions described and depicted hereininclude a method and system for redaction and reconciliation of adocument in blockchain networks. The exemplary embodiments solve theissues of time and trust by extending features of a database such asimmutability, digital signatures and being a single source of truth. Theexemplary embodiments provide a solution for redaction andreconciliation of a document in blockchain-based network. The blockchainnetworks may be homogenous based on the asset type and rules that governthe assets based on the smart contracts.

Blockchain is different from a traditional database in that blockchainis not a central storage, but rather a decentralized, immutable, andsecure storage, where nodes must share in changes to records in thestorage. Some properties that are inherent in blockchain and which helpimplement the blockchain include, but are not limited to, an immutableledger, smart contracts, security, privacy, decentralization, consensus,endorsement, accessibility, and the like, which are further describedherein. According to various aspects, the system for redaction andreconciliation of a document in blockchain networks is implemented dueto immutable accountability, security, privacy, permitteddecentralization, availability of smart contracts, endorsements andaccessibility that are inherent and unique to blockchain. In particular,the blockchain ledger data is immutable and that provides for efficientmethod for redaction and reconciliation of a document in blockchainnetworks. Also, use of the encryption in the blockchain providessecurity and builds trust. The smart contract manages the state of theasset to complete the life-cycle. The example blockchains are permissiondecentralized. Thus, each end user may have its own ledger copy toaccess. Multiple organizations (and peers) may be on-boarded on theblockchain network. The key organizations may serve as endorsing peersto validate the smart contract execution results, read-set andwrite-set. In other words, the blockchain inherent features provide forefficient implementation of a method for redaction and reconciliation ofa document.

One of the benefits of the example embodiments is that it improves thefunctionality of a computing system by implementing a method forredaction and reconciliation of a document in blockchain-based systems.Through the blockchain system described herein, a computing system canperform functionality for redaction and reconciliation of a document inblockchain networks by providing access to capabilities such asdistributed ledger, peers, encryption technologies, MSP, event handling,etc. Also, the blockchain enables to create a business network and makeany users or organizations to on-board for participation. As such, theblockchain is not just a database. The blockchain comes withcapabilities to create a Business Network of users andon-board/off-board organizations to collaborate and execute serviceprocesses in the form of smart contracts.

The example embodiments provide numerous benefits over a traditionaldatabase. For example, through the blockchain the embodiments providefor immutable accountability, security, privacy, permitteddecentralization, availability of smart contracts, endorsements andaccessibility that are inherent and unique to the blockchain.

Meanwhile, a traditional database could not be used to implement theexample embodiments because it does not bring all parties on thebusiness network, it does not create trusted collaboration and does notprovide for an efficient storage of digital assets. The traditionaldatabase does not provide for a tamper proof storage and does notprovide for preservation of the digital assets being stored. Thus, theproposed method for redaction and reconciliation of a document inblockchain networks cannot be implemented in the traditional database.

Meanwhile, if a traditional database were to be used to implement theexample embodiments, the example embodiments would have suffered fromunnecessary drawbacks such as search capability, lack of security andslow speed of transactions. Additionally, the automated method forredaction and reconciliation of a document in the blockchain networkwould simply not be possible.

Accordingly, the example embodiments provide for a specific solution toa problem in the arts/field of asset access management in the blockchainnetworks.

The example embodiments also change how data may be stored within ablock structure of the blockchain. For example, a digital asset data maybe securely stored within a certain portion of the data block (i.e.,within header, data segment, or metadata). By storing the digital assetdata within data blocks of a blockchain, the digital asset data may beappended to an immutable blockchain ledger through a hash-linked chainof blocks. In some embodiments, the data block may be different than atraditional data block by having a personal data associated with thedigital asset not stored together with the assets within a traditionalblock structure of a blockchain. By removing the personal dataassociated with the digital asset, the blockchain can provide thebenefit of anonymity based on immutable accountability and security.

According to the exemplary embodiments, a system and method for handlingof electronic documents containing protected information are provided.The exemplary embodiments permit for a secure redaction, distribution,and reconciliation of documents involving complex cases where multipleparties are involved. In some cases each party may have a differentprivilege level applied to certain document segments. The exemplaryembodiments may create a fast and secure reconciliation flow. A system(i.e., a document server), in accordance to the exemplary embodiment,may accept edits from authorized users, then it may dispatch theproposed changes to an approval flow (if set by the owner). The documentserver may tally the votes for consensus, and then it may reconcile thedifferences back into the original document. Finally, the documentserver provides a real-time update notification to all users includingviewers of a redacted document version. In simple terms, everyone worksoff the master document, even the redacted viewers.

In a sensitive document, which needs restricted access control levels(ACL), the owner may define who has access to which portions of thedocument and specifies view (read) or edit (write) access for eachportion/segment (word, sentence, paragraph, spreadsheet cell, column,row, etc.) of the document. The document owner may also define theconsensus method for reconciling document edits. The owner may, forexample, select consensus as “all voters must agree” or “most votersmust agree.” Finally, the owner may assign voters that can accept orreject the proposed edits. After this initial set up, the owner maypublish his changes to a document server (e.g., a cloud server). Thedocument server then parses the document, splitting it into multipleledger entries for blockchain storage. From that point, the blockchainenforces the access to each document portion, such that only authorizedusers can obtain view or edit access to the document or may vote on eachsegment, as defined by the owner via an application (e.g., a wordprocessing application or similar). When an authorized editor performs achange to the document, the ledger entry for that segment is updatedwith the proposed change. The voters must then approve or reject thechange. Once the voting is concluded, the votes are tallied up, and uponconsensus the update is marked as proposed. The update must be voted perrules set by a block, before the editor's changes become effective.

In one exemplary embodiment, upon voting completion, results are talliedand if there is a change to the original document, all viewer nodes geta real-time notification of the document updates. For example, theupdates may be provided via a word processing application or anotherspecial application. If there is no consensus on the proposed changes, anew ledger entry is generated to reflect rejection of the editor'sproposed changes.

According to one exemplary embodiment, security is strictly enforcedusing smart contracts running on a blockchain fabric. In other words,the security is not something that has to be “added in” as an option toan existing document, because the security is built into the entireblockchain process. The document server tokenizes a document intosegments and stores the segments into blockchain ledger entries thatprovide fine-grained access control levels. The document server createsa single source of truth, regardless of a user's access control level,hence eliminating multiple copies of the same document. An unauthorizeduser does not have to see the entire document to make a change to acertain portion. Configuration of the consensus rules may be implementedat a segment level. Consensus is enforced by the smart contracts on theblockchain fabric. The document server connected to the blockchainprovides for an end to end solution—i.e., redaction, distribution, andreconciliation of document may occur seamlessly and entirely within anencrypted space as defined by the smart contracts on the blockchainfabric. According to one exemplary embodiment, CRUD (Create, Read,Update, and Delete) operations may be enabled for a document entirelywithin an encrypted space so that there is never a moment that anunencrypted version of the document is stored on the client's disk. Thedocument server may provide real-time update notifications to all usersincluding viewers of a redacted document version.

According to the exemplary embodiments, a user may create a new documentin the word processing application. This user becomes the documentowner. That initial document may be referred to as the seed document andis the source of truth. The owner is given full rights to compose andrestrict the seed document's access. The word processing application (orother application that may produce the seed document) may connect to thedocument server (e.g., a cloud server) using CRUD-based calls. Thedocument server may manage the document lifecycle, such as rendering,editing, and voting for changes. The document owner may decide tosecurely allow others to view or edit portions (i.e., segments) of thedocument. The owner may then select a portion(s) of the document and mayassign access level to the portion(s) along with the authorized users.For example, the document owner may highlight and restrict access to atext segment “dolor sit amet” to a user Mary. The result may be intendedas a segment to be redacted out for a user John. Then, the owner mayhighlight the word “labore” to give edit access to an authorized userMary. The document owner may at this time (optionally) define and selectthe consensus method and may assign which participants are to vote toapprove Mary's changes. Additionally, view, edit, or vote permissionsmay have an expiration date. The document owner may publish his changes(i.e., may either create a new document or may alter an existing one) tothe document server. The document server may split the document intoseparate transactions in a manner that is compatible with the selectedblockchain technology in the implementation (Hyperledger, Ethereum,etc.). Then, the document server may submit transaction(s) to update theblockchain ledger.

In one embodiment, parsing and splitting of the seed document may beimplemented using a parent-child data model, which defines master andchild components. The following three ledger entry classes may be used:

(1) MASTER DOCUMENT RECORD (MDR);

(2) CHILD RECORD; and

(3) ACCESS CONTROL LIST (ACL).

Concept of PARTICIPANT, ASSET, and TRANSACTIONS may be used. The MDRcontains references to CHILD RECORDS and the ACCESS CONTROL LIST (ACL).These artifacts are based on the specifications generated by thedocument server. Each child record represents a segment that is redactedfor different participants. The ACL document contains the permissionsfor each child document specified. For example, a transaction mayindicate that only Oscar and Mary can write to the child record withdocument id “z”. The MDR may also contain information on how the childelements should be assembled, so that the word processing application(or similar client application) can render the final document view. Thisallows users recreate a version of the seed document containing theuser-specific viewing, editing and voting privileges. For example, theMDR may show the following child element: [[‘x’, 0], [‘y’,0], [‘x’,[‘z’, 0], [‘x’, 2]], where the first value pair ([‘x’, 0]), is decodedas follows: ‘x’ is the child document id, the second value “0” is thechild's value index. The value pair ([‘x’, 0]) indicates which segmentof the child document is to be rendered. Note that a child record mayhave multiple segments stored in it. The MDR may contain documentrendering logic. For example, the MDR child may show that renderingtakes place by first taking a pair [‘x’, 0], where child document is‘x’, an value index is 0. The document server may evaluate the ACL (sentin a transaction) and then fetch document X (sent in anothertransaction). The document may be retrieved either by fetching thecorresponding block directly or by reading a world state database. Forexample, the document ‘x’, index 0 has the value of “Lorem ipsum”. Thus,this segment needs to be rendered first. The next element to be renderedis [‘y’, 0], and the above process may be repeated until all childelements listed in the MDR are evaluated.

In one example, a child record ‘z’ may require approvals for a proposedchange from either the document owner or from both Paul and Peter. Onceapproved, the change(s) may be reflected to the subscribing users. Inone embodiment, each ledger entry may include creation and updatetimestamps and version number(s). The child record may include othermetadata such as PCI-type of data. The child record may make referenceto another child record and or an object located at another source(e.g., off the blockchain storage).This may be used for embedding oflarge data such as video files. A client application (e.g., wordprocessing application) may subscribe to the document server (e.g., acloud server) to receive real-time updates on changes to the document ofinterest. In one embodiment, read-only users may not receivenotifications on the proposed changes, but may only receive thenotification on the committed/voted changes. The subscription mechanismmay be implemented using WebSockets and a queue (RabbitMQ, Kafka) orother equivalent technology. This may allow for a simultaneous documentediting and for an instant notification of two users making conflictingchanges to a text segment. In another embodiment, a document may be, forexample, an MS EXCEL spreadsheet, MS Visio, or MS EXCEL document, vectorgraphics, or layer-based computer-aided design (CAD) document. This mayallow, for example, a blueprint of a building (or of a city) to beshared with contractors on an as-needed basis without revealingsensitive information about the entire infrastructure. In anotherembodiment, Hyperledger Composer solutions may be used.

In one exemplary embodiment, a client application may accept an ID cardas an input. The client application may consume REST APIs exposed forthe contract and may aggregate the document accordingly for eachparticipant based on the role and access control defined for theparticipant. Additional security can be enforced by mechanisms likeenforcing an ID login into nthe application before allowing the ID cardto be imported and associating the ID card and the login credentials.Storing and managing of assets on the blockchain can be accomplished inseveral ways. If the size of the asset/asset segments is not a concern,the asset can be converted into blob(s) and stored directly in theblockchain if the participants in the network are willing and the costis acceptable. One important thing to note is that the transactions arereplicated in a blockchain solution, so if storage is a concern otheroff-chain solutions may be used. Other reasons for the off-chain storagemay be the owner not wanting the document/segments distributed acrossthe network, but rather stored in a secure trusted location (or legal/government requirements that require a specific kind of centralizedstorage). In cases of the off-chain storage, instead storing of theactual document segments/child documents, hashes referencing the asset(i.e., a document) may be stored on the blockchain.

FIG. 1B illustrates a logic network diagram for redaction andreconciliation of a document in a blockchain network, according toexample embodiments.

Referring to FIG. 1B, the example network 100 includes a document server102 connected to document owner nodes 105 and to other participant nodes107. The document server 102 may be connected to a blockchain 106 thathas a ledger 108 for storing ledger entries 110. While this exampledescribes in detail only one document server 102, multiple such nodesmay be connected to the blockchain 106. It should be understood that thedocument server 102 may include additional components and that some ofthe components described herein may be removed and/or modified withoutdeparting from a scope of the document server 102 disclosed herein. Thedocument server 102 may be a computing device or a server computer, orthe like, and may include a processor 104, which may be asemiconductor-based microprocessor, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), a field-programmableprogrammable gate array (FPGA), and/or another hardware device. Althougha single processor 104 is depicted, it should be understood that thedocument server 102 may include multiple processors, multiple cores, orthe like, without departing from the scope of the document server node102 system.

The document server 102 may also include a non-transitory computerreadable medium 112 that may have stored thereon machine-readableinstructions executable by the processor 104. Examples of themachine-readable instructions are shown as 114-122 and are furtherdiscussed below. Examples of the non-transitory computer readable medium112 may include an electronic, magnetic, optical, or other physicalstorage device that contains or stores executable instructions. Forexample, the non-transitory computer readable medium 112 may be a RandomAccess memory (RAM), an Electrically Erasable Programmable Read-OnlyMemory (EEPROM), a hard disk, an optical disc, or other type of storagedevice.

The processor 104 may fetch, decode, and execute the machine-readableinstructions 114 to receive a document from a document owner node 105.The document may contain restricted access segments. As discussed above,the blockchain ledger 108 may store the segments of a seed document in aform of ledger entries 110. The blockchain 106 network may be configuredto use one or more smart contracts that manage transactions for multipleparticipating nodes. The document server 102 may provide real-timenotifications to the nodes 105 and 107.

The processor 104 may fetch, decode, and execute the machine-readableinstructions 116 to split the document into a plurality of ledgerentries 110 to be stored on a blockchain 106. The processor 104 mayfetch, decode, and execute the machine-readable instructions 118 toupdate a ledger entry of the plurality of ledger entries based on aproposed change to the document made by an authorized participant node.The processor 104 may fetch, decode, and execute the machine-readableinstructions 120 to commit the ledger entry to the blockchain based onvotes collected from a plurality of participant nodes 107. The processor104 may fetch, decode, and execute the machine-readable instructions 122to send a notification to a set of participant nodes of the plurality ofthe participant nodes 107 authorized to view the document.

FIG. 1B illustrates a logic network diagram for redaction andreconciliation of a document in a blockchain network, according toexample embodiments.

Referring to FIG. 1B, the example network 101 includes a document server102 connected to document owner nodes 105 and to other participant nodes107. The document server 102 may be connected to a blockchain 106 thathas a ledger 101 for storing ledger entries 110. While this exampledescribes in detail only one document server 102, multiple such nodesmay be connected to the blockchain 106. It should be understood that thedocument server 102 may include additional components and that some ofthe components described herein may be removed and/or modified withoutdeparting from a scope of the document server 102 disclosed herein. Thedocument server 102 may be a computing device or a server computer, orthe like, and may include a processor 104, which may be asemiconductor-based microprocessor, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), a field-programmablegate array (FPGA), and/or another hardware device. Although a singleprocessor 104 is depicted, it should be understood that the documentserver 102 may include multiple processors, multiple cores, or the like,without departing from the scope of the document server node 102 system.

The document server 102 may also include a non-transitory computerreadable medium 112 that may have stored thereon machine-readableinstructions executable by the processor 104. Examples of themachine-readable instructions are shown as 113-121 and are furtherdiscussed below. Examples of the non-transitory computer readable medium112 may include an electronic, magnetic, optical, or other physicalstorage device that contains or stores executable instructions. Forexample, the non-transitory computer readable medium 112 may be a RandomAccess memory (RAM), an Electrically Erasable Programmable Read-OnlyMemory (EEPROM), a hard disk, an optical disc, or other type of storagedevice.

The processor 104 may fetch, decode, and execute the machine-readableinstructions 113 to split a document provided by a document owner node105 into a plurality of segments to be stored on a ledger of ablockchain 106. As discussed above, the blockchain ledger 101 may storethe segments of a seed document in a form of ledger entries 110. Theblockchain 106 network may be configured to use one or more smartcontracts that manage transactions for multiple participating nodes. Thedocument server 102 may provide real-time notifications to the nodes 105and 107.

The processor 104 may fetch, decode, and execute the machine-readableinstructions 115 to detect a change to the document made by anauthorized participant node 107. The processor 104 may fetch, decode,and execute the machine-readable instructions 117 to update a segment ofthe plurality of segments stored on the ledger 101 based on the changeto the document. The processor 104 may fetch, decode, and execute themachine-readable instructions 119 collect votes on the change to thedocument from a plurality of participant nodes 107. The processor 104may fetch, decode, and execute the machine-readable instructions 121 tocommit the updated segment to the blockchain 106 based on the votes.

FIG. 2A illustrates a blockchain architecture configuration 200,according to example embodiments. Referring to FIG. 2A, the blockchainarchitecture 200 may include certain blockchain elements, for example, agroup of blockchain nodes 202. The blockchain nodes 202 may include oneor more nodes 204-210 (these four nodes are depicted by example only).These nodes participate in a number of activities, such as blockchaintransaction addition and validation process (consensus). One or more ofthe blockchain nodes 204-210 may endorse transactions based onendorsement policy and may provide an ordering service for allblockchain nodes in the architecture 200. A blockchain node may initiatea blockchain authentication and seek to write to a blockchain immutableledger stored in blockchain layer 216, a copy of which may also bestored on the underpinning physical infrastructure 214. The blockchainconfiguration may include one or more applications 224which are linkedto application programming interfaces (APIs) 222 to access and executestored program/application code 220 (e.g., chaincode, smart contracts,etc.) which can be created according to a customized configurationsought by participants and can maintain their own state, control theirown assets, and receive external information. This can be deployed as atransaction and installed, via appending to the distributed ledger, onall blockchain nodes 204-210.

The blockchain base or platform 212 may include various layers ofblockchain data, services (e.g., cryptographic trust services, virtualexecution environment, etc.), and underpinning physical computerinfrastructure that may be used to receive and store new transactionsand provide access to auditors which are seeking to access data entries.The blockchain layer 216 may expose an interface that provides access tothe virtual execution environment necessary to process the program codeand engage the physical infrastructure 214. Cryptographic trust services218 may be used to verify transactions such as asset exchangetransactions and keep information private.

The blockchain architecture configuration of FIG. 2A may process andexecute program/application code 220 via one or more interfaces exposed,and services provided, by blockchain platform 212. The code 220 maycontrol blockchain assets. For example, the code 220 can store andtransfer data, and may be executed by nodes 204-210 in the form of asmart contract and associated chaincode with conditions or other codeelements subject to its execution. As a non-limiting example, smartcontracts may be created to execute reminders, updates, and/or othernotifications subject to the changes, updates, etc. The smart contractscan themselves be used to identify rules associated with authorizationand access requirements and usage of the ledger. For example, the seeddocument information 226 may be processed by one or more processingentities (e.g., virtual machines) included in the blockchain layer 216.The result 228 may include data blocks reflecting changes to the seeddocument. The physical infrastructure 214 may be utilized to retrieveany of the data or information described herein.

A smart contract may be created via a high-level application andprogramming language, and then written to a block in the blockchain. Thesmart contract may include executable code which is registered, stored,and/or replicated with a blockchain (e.g., distributed network ofblockchain peers). A transaction is an execution of the smart contractcode which can be performed in response to conditions associated withthe smart contract being satisfied. The executing of the smart contractmay trigger a trusted modification(s) to a state of a digital blockchainledger. The modification(s) to the blockchain ledger caused by the smartcontract execution may be automatically replicated throughout thedistributed network of blockchain peers through one or more consensusprotocols.

The smart contract may write data to the blockchain in the format ofkey-value pairs. Furthermore, the smart contract code can read thevalues stored in a blockchain and use them in application operations.The smart contract code can write the output of various logic operationsinto the blockchain. The code may be used to create a temporary datastructure in a virtual machine or other computing platform. Data writtento the blockchain can be public and/or can be encrypted and maintainedas private. The temporary data that is used/generated by the smartcontract is held in memory by the supplied execution environment, thendeleted once the data needed for the blockchain is identified.

A chaincode may include the code interpretation of a smart contract,with additional features. As described herein, the chaincode may beprogram code deployed on a computing network, where it is executed andvalidated by chain validators together during a consensus process. Thechaincode receives a hash and retrieves from the blockchain a hashassociated with the data template created by use of a previously storedfeature extractor. If the hashes of the hash identifier and the hashcreated from the stored identifier template data match, then thechaincode sends an authorization key to the requested service. Thechaincode may write to the blockchain data associated with thecryptographic details.

FIG. 2B illustrates an example of a blockchain transactional flow 250between nodes of the blockchain in accordance with an exampleembodiment. Referring to FIG. 2B, the transaction flow may include atransaction proposal 291 sent by an application client node 260 to anendorsing peer node 281. The endorsing peer 281 may verify the clientsignature and execute a chaincode function to initiate the transaction.The output may include the chaincode results, a set of key/valueversions that were read in the chaincode (read set), and the set ofkeys/values that were written in chaincode (write set). The proposalresponse 292 is sent back to the client 260 along with an endorsementsignature, if approved. The client 260 assembles the endorsements into atransaction payload 293 and broadcasts it to an ordering service node284. The ordering service node 284 then delivers ordered transactions asblocks to all peers 281-283 on a channel. Before committal to theblockchain, each peer 281-283 may validate the transaction. For example,the peers may check the endorsement policy to ensure that the correctallotment of the specified peers have signed the results andauthenticated the signatures against the transaction payload 293.

Referring again to FIG. 2B, the client node 260 initiates thetransaction 291 by constructing and sending a request to the peer node281, which is an endorser. The client 260 may include an applicationleveraging a supported software development kit (SDK), which utilizes anavailable API to generate a transaction proposal. The proposal is arequest to invoke a chaincode function so that data can be read and/orwritten to the ledger (i.e., write new key value pairs for the assets).The SDK may serve as a shim to package the transaction proposal into aproperly architected format (e.g., protocol buffer over a remoteprocedure call (RPC)) and take the client's cryptographic credentials toproduce a unique signature for the transaction proposal.

In response, the endorsing peer node 281 may verify (a) that thetransaction proposal is well formed, (b) the transaction has not beensubmitted already in the past (replay-attack protection), (c) thesignature is valid, and (d) that the submitter (client 260, in theexample) is properly authorized to perform the proposed operation onthat channel. The endorsing peer node 281 may take the transactionproposal inputs as arguments to the invoked chaincode function. Thechaincode is then executed against a current state database to producetransaction results including a response value, read set, and write set.However, no updates are made to the ledger at this point. In 292, theset of values, along with the endorsing peer node's 281 signature ispassed back as a proposal response 292 to the SDK of the client 260which parses the payload for the application to consume.

In response, the application of the client 260 inspects/verifies theendorsing peers' signatures and compares the proposal responses todetermine if the proposal response is the same. If the chaincode onlyqueried the ledger, the application would inspect the query response andwould typically not submit the transaction to the ordering node service284. If the client application intends to submit the transaction to theordering node service 284 to update the ledger, the applicationdetermines if the specified endorsement policy has been fulfilled beforesubmitting (i.e., did all peer nodes necessary for the transactionendorse the transaction). Here, the client may include only one ofmultiple parties to the transaction. In this case, each client may havetheir own endorsing node, and each endorsing node will need to endorsethe transaction. The architecture is such that even if an applicationselects not to inspect responses or otherwise forwards an unendorsedtransaction, the endorsement policy will still be enforced by peers andupheld at the commit validation phase.

After successful inspection, in step 293 the client 260 assemblesendorsements into a transaction and broadcasts the transaction proposaland response within a transaction message to the ordering node 284. Thetransaction may contain the read/write sets, the endorsing peers'signatures and a channel ID. The ordering node 284 does not need toinspect the entire content of a transaction in order to perform itsoperation, instead the ordering node 284 may simply receive transactionsfrom all channels in the network, order them chronologically by channel,and create blocks of transactions per channel.

The blocks of the transaction are delivered from the ordering node 284to all peer nodes 281-283 on the channel. The transactions 294 withinthe block are validated to ensure any endorsement policy is fulfilledand to ensure that there have been no changes to ledger state for readset variables since the read set was generated by the transactionexecution. Transactions in the block are tagged as being valid orinvalid. Furthermore, in step 295 each peer node 281-283 appends theblock to the channel's chain, and for each valid transaction the writesets are committed to current state database. An event is emitted, tonotify the client application that the transaction (invocation) has beenimmutably appended to the chain, as well as to notify whether thetransaction was validated or invalidated.

FIG. 3A illustrates an example of a permissioned blockchain network 300,which features a distributed, decentralized peer-to-peer architecture.In this example, a blockchain user 302 may initiate a transaction to thepermissioned blockchain 304. In this example, the transaction can be adeploy, invoke, or query, and may be issued through a client-sideapplication leveraging an SDK, directly through an API, etc. Networksmay provide access to a regulator 306, such as an auditor. A blockchainnetwork operator 308 manages member permissions, such as enrolling theregulator 306 as an “auditor” and the blockchain user 302 as a “client”.An auditor could be restricted only to querying the ledger whereas aclient could be authorized to deploy, invoke, and query certain types ofchaincode.

A blockchain developer 310 can write chaincode and client-sideapplications. The blockchain developer 310 can deploy chaincode directlyto the network through an interface. To include credentials from atraditional data source 312 in chaincode, the developer 310 could use anout-of-band connection to access the data. In this example, theblockchain user 302 connects to the permissioned blockchain 304 througha peer node 314. Before proceeding with any transactions, the peer node314 retrieves the user's enrollment and transaction certificates from acertificate authority 316, which manages user roles and permissions. Insome cases, blockchain users must possess these digital certificates inorder to transact on the permissioned blockchain 304. Meanwhile, a userattempting to utilize chaincode may be required to verify theircredentials on the traditional data source 312. To confirm the user'sauthorization, chaincode can use an out-of-band connection to this datathrough a traditional processing platform 318.

FIG. 3B illustrates another example of a permissioned blockchain network320, which features a distributed, decentralized peer-to-peerarchitecture. In this example, a blockchain user 322 may submit atransaction to the permissioned blockchain 324. In this example, thetransaction can be a deploy, invoke, or query, and may be issued througha client-side application leveraging an SDK, directly through an API,etc. Networks may provide access to a regulator 326, such as an auditor.A blockchain network operator 328 manages member permissions, such asenrolling the regulator 326 as an “auditor” and the blockchain user 322as a “client”. An auditor could be restricted only to querying theledger whereas a client could be authorized to deploy, invoke, and querycertain types of chaincode.

A blockchain developer 330 writes chaincode and client-sideapplications. The blockchain developer 330 can deploy chaincode directlyto the network through an interface. To include credentials from atraditional data source 332 in chaincode, the developer 330 could use anout-of-band connection to access the data. In this example, theblockchain user 322 connects to the network through a peer node 334.Before proceeding with any transactions, the peer node 334 retrieves theuser's enrollment and transaction certificates from the certificateauthority 336. In some cases, blockchain users must possess thesedigital certificates in order to transact on the permissioned blockchain324. Meanwhile, a user attempting to utilize chaincode may be requiredto verify their credentials on the traditional data source 332. Toconfirm the user's authorization, chaincode can use an out-of-bandconnection to this data through a traditional processing platform 338.

FIG. 4A illustrates a flow diagram 400 of an example method forredaction and reconciliation of a document in blockchain networks,according to example embodiments. Referring to FIG. 4A, the method 400may include one or more of the steps described below.

FIG. 4A illustrates a flow chart of an example method executed by thedocument server 102 (see FIG. 1). It should be understood that method400 depicted in FIG. 4A may include additional operations and that someof the operations described therein may be removed and/or modifiedwithout departing from the scope of the method 400. The description ofthe method 400 is also made with reference to the features depicted inFIG. 1 for purposes of illustration. Particularly, the processor 104 ofthe document server 102 may execute some or all of the operationsincluded in the method 400.

With reference to FIG. 4A, at block 412, the processor 104 may receive adocument from a document owner node. The document may contain restrictedaccess segments. At block 414, the processor 104 may split the documentinto a plurality of ledger entries to be stored on a blockchain. Atblock 416, the processor 104 may update a ledger entry of the pluralityof ledger entries based on a proposed change to the document made by anauthorized participant node. At block 418, the processor 104 may committhe ledger entry to the blockchain based on votes collected from aplurality of participant nodes. At block 420, the processor 104 may senda notification to a set of participant nodes of the plurality of theparticipant nodes authorized to view the document.

FIG. 4B illustrates a flow diagram 450 of an example method forredaction and reconciliation of a document in a blockchain network,according to example embodiments. Referring to FIG. 4B, the method 450may also include one or more of the following steps. At block 452, theprocessor 104 may determine view and edit access for each of therestricted access segments of the document for the plurality of theparticipant nodes. At block 454, the processor 104 may determine aconsensus method for reconciliation of changes of the document based oninstructions received from the document owner. At block 456, theprocessor 104 may assign participant nodes from the plurality of theparticipant nodes to vote on the proposed change as defined by thedocument owner. At block 458, the processor 104 may generate a ledgerentry that indicates rejection of the proposed change if consensus isnot reached by the participant nodes assigned to vote. At block 460, theprocessor 104 may execute a smart contract to restrict access to thesegments of the document. At block 462, the processor 104 may convertthe ledger entries into blobs prior to their storage on the blockchain.

FIG. 4C illustrates a flow diagram 410 of an example method forredaction and reconciliation of a document in blockchain networks,according to example embodiments. Referring to FIG. 4C, the method 410may include one or more of the steps described below.

FIG. 4C illustrates a flow chart of an example method executed by thedocument server 102 (see FIG. 1A). It should be understood that method410 depicted in FIG. 4C may include additional operations and that someof the operations described therein may be removed and/or modifiedwithout departing from the scope of the method 410. The description ofthe method 410 is also made with reference to the features depicted inFIG. 1A for purposes of illustration. Particularly, the processor 104 ofthe document server 102 may execute some or all of the operationsincluded in the method 410.

With reference to FIG. 4C, at block 413, the processor 104 may split adocument provided by a document owner node into a plurality of segmentsto be stored on a ledger of a blockchain. At block 415, the processor104 may detect a change to the document made by an authorizedparticipant node. At block 417, the processor 104 may update a segmentof the plurality of segments stored on the ledger based on the change tothe document. At block 419, the processor 104 may collect votes on thechange to the document from a plurality of participant nodes. At block421, the processor 104 may commit the updated segment to the blockchainbased on the votes.

FIG. 4D illustrates a flow diagram 470 of an example method forredaction and reconciliation of a document in a blockchain network,according to example embodiments. Referring to FIG. 4D, the method 470may also include one or more of the following steps. At block 472, theprocessor 104 may send a notification of the change to the document to aset of participant nodes of the plurality of the participant nodesauthorized to view the document. At block 474, the processor 104 maydetermine view and edit access for each of the segments of the documentfor the plurality of the participant nodes. At block 476, the processor104 may receive instructions from the document owner on a consensusmethod for reconciliation of changes of the document. At block 478, theprocessor 104 may assign participant nodes selected by the documentowner from the plurality of the participant nodes to vote on thedocument change. At block 480, the processor 104 may record a ledgerentry on the blockchain if a consensus on the document change is notreached by the participant nodes assigned to vote. At block 482, theprocessor 104 may execute a smart contract to restrict access to thesegments of the document identified by the document owner.

FIG. 5A illustrates an example system 600 that includes a physicalinfrastructure 510 configured to perform various operations according toexample embodiments. Referring to FIG. 5A, the physical infrastructure510 includes a module 512 and a module 514. The module 514 includes ablockchain 520 and a smart contract 530 (which may reside on theblockchain 520), that may execute any of the operational steps 508 (inmodule 512) included in any of the example embodiments. Thesteps/operations 508 may include one or more of the embodimentsdescribed or depicted and may represent output or written informationthat is written or read from one or more smart contracts 530 and/orblockchains 520. The physical infrastructure 510, the module 512, andthe module 514 may include one or more computers, servers, processors,memories, and/or wireless communication devices. Further, the module 512and the module 514 may be a same module.

FIG. 5B illustrates another example system 540 configured to performvarious operations according to example embodiments. Referring to FIG.6B, the system 640 includes a module 512 and a module 514. The module514 includes a blockchain 520 and a smart contract 530 (which may resideon the blockchain 520), that may execute any of the operational steps508 (in module 512) included in any of the example embodiments. Thesteps/operations 508 may include one or more of the embodimentsdescribed or depicted and may represent output or written informationthat is written or read from one or more smart contracts 530 and/orblockchains 520. The physical infrastructure 510, the module 512, andthe module 514 may include one or more computers, servers, processors,memories, and/or wireless communication devices. Further, the module 512and the module 514 may be a same module.

FIG. 5C illustrates an example system configured to utilize a smartcontract configuration among contracting parties and a mediating serverconfigured to enforce the smart contract terms on the blockchainaccording to example embodiments. Referring to FIG. 5C, theconfiguration 550 may represent a communication session, an assettransfer session or a process or procedure that is driven by a smartcontract 530 which explicitly identifies one or more user devices 552and/or 556. The execution, operations and results of the smart contractexecution may be managed by a server 554. Content of the smart contract530 may require digital signatures by one or more of the entities 552and 556 which are parties to the smart contract transaction. The resultsof the smart contract execution may be written to a blockchain 520 as ablockchain transaction. The smart contract 530 resides on the blockchain520 which may reside on one or more computers, servers, processors,memories, and/or wireless communication devices.

FIG. 5D illustrates a system 560 including a blockchain, according toexample embodiments. Referring to the example of FIG. 5D, an applicationprogramming interface (API) gateway 562 provides a common interface foraccessing blockchain logic (e.g., smart contract 530 or other chaincode)and data (e.g., distributed ledger, etc.). In this example, the APIgateway 562 is a common interface for performing transactions (invoke,queries, etc.) on the blockchain by connecting one or more entities 552and 556 to a blockchain peer (i.e., server 554). Here, the server 554 isa blockchain network peer component that holds a copy of the world stateand a distributed ledger allowing clients 552 and 556 to query data onthe world state as well as submit transactions into the blockchainnetwork where, depending on the smart contract 530 and endorsementpolicy, endorsing peers will run the smart contracts 530.

The above embodiments may be implemented in hardware, in a computerprogram executed by a processor, in firmware, or in a combination of theabove. A computer program may be embodied on a computer readable medium,such as a storage medium. For example, a computer program may reside inrandom access memory (“RAM”), flash memory, read-only memory (“ROM”),erasable programmable read-only memory (“EPROM”), electrically erasableprogrammable read-only memory (“EEPROM”), registers, hard disk, aremovable disk, a compact disk read-only memory (“CD-ROM”), or any otherform of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such thatthe processor may read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anapplication specific integrated circuit (“ASIC”). In the alternative,the processor and the storage medium may reside as discrete components.

FIG. 6A illustrates a process 600 of a new block being added to adistributed ledger 620, according to example embodiments, and FIG. 6Billustrates contents of a new data block structure 630 for blockchain,according to example embodiments. Referring to FIG. 6A, clients (notshown) may submit transactions to blockchain nodes 611, 612, and/or 613.Clients may execute be instructions received from any source to enactactivity on the blockchain 620. As an example, clients may beapplications that act on behalf of a requester, such as a device, personor entity to propose transactions for the blockchain. The plurality ofblockchain peers (e.g., blockchain nodes 611, 612, and 613) may maintaina state of the blockchain network and a copy of the distributed ledger620. Different types of blockchain nodes/peers may be present in theblockchain network including endorsing peers which simulate and endorsetransactions proposed by clients and committing peers which verifyendorsements, validate transactions, and commit transactions to thedistributed ledger 620. In this example, the blockchain nodes 611, 612,and 613 may perform the role of endorser node, committer node, or both.

The distributed ledger 620 includes a blockchain which stores immutable,sequenced records in blocks, and a state database 624 (current worldstate) maintaining a current state of the blockchain 622. Onedistributed ledger 620 may exist per channel and each peer maintains itsown copy of the distributed ledger 620 for each channel of which theyare a member. The blockchain 622 is a transaction log, structured ashash-linked blocks where each block contains a sequence of Ntransactions. Blocks may include various components such as shown inFIG. 6B. The linking of the blocks (shown by arrows in FIG. 6A) may begenerated by adding a hash of a prior block's header within a blockheader of a current block. In this way, all transactions on theblockchain 622 are sequenced and cryptographically linked togetherpreventing tampering with blockchain data without breaking the hashlinks. Furthermore, because of the links, the latest block in theblockchain 622 represents every transaction that has come before it. Theblockchain 622 may be stored on a peer file system (local or attachedstorage), which supports an append-only blockchain workload.

The current state of the blockchain 622 and the distributed ledger 622may be stored in the state database 624. Here, the current state datarepresents the latest values for all keys ever included in the chaintransaction log of the blockchain 622. Chaincode invocations executetransactions against the current state in the state database 624. Tomake these chaincode interactions extremely efficient, the latest valuesof all keys are stored in the state database 624. The state database 624may include an indexed view into the transaction log of the blockchain622, it can therefore be regenerated from the chain at any time. Thestate database 624 may automatically get recovered (or generated ifneeded) upon peer startup, before transactions are accepted.

Endorsing nodes receive transactions from clients and endorse thetransaction based on simulated results. Endorsing nodes hold smartcontracts which simulate the transaction proposals. When an endorsingnode endorses a transaction, the endorsing node creates a transactionendorsement which is a signed response from the endorsing node to theclient application indicating the endorsement of the simulatedtransaction. The method of endorsing a transaction depends on anendorsement policy which may be specified within chaincode. An exampleof an endorsement policy is “the majority of endorsing peers mustendorse the transaction”. Different channels may have differentendorsement policies. Endorsed transactions are forward by the clientapplication to ordering service 610.

The ordering service 610 accepts endorsed transactions, orders them intoa block, and delivers the blocks to the committing peers. For example,the ordering service 610 may initiate a new block when a threshold oftransactions has been reached, a timer times out, or another condition.In the example of FIG. 6A, blockchain node 612 is a committing peer thathas received a new data new data block 630 for storage on blockchain620. The first block in the blockchain may be referred to as a genesisblock which includes information about the blockchain, its members, thedata stored therein, etc.

The ordering service 610 may be made up of a cluster of orderers. Theordering service 610 does not process transactions, smart contracts, ormaintain the shared ledger. Rather, the ordering service 610 may acceptthe endorsed transactions and specifies the order in which thosetransactions are committed to the distributed ledger 620. Thearchitecture of the blockchain network may be designed such that thespecific implementation of ‘ordering’ (e.g., Solo, Kafka, BFT, etc.)becomes a pluggable component.

Transactions are written to the distributed ledger 620 in a consistentorder. The order of transactions is established to ensure that theupdates to the state database 624 are valid when they are committed tothe network. Unlike a crypto-currency blockchain system (e.g., Bitcoin,etc.) where ordering occurs through the solving of a cryptographicpuzzle, or mining, in this example the parties of the distributed ledger620 may choose the ordering mechanism that best suits that network.

When the ordering service 610 initializes a new data block 630, the newdata block 630 may be broadcast to committing peers (e.g., blockchainnodes 611, 612, and 613). In response, each committing peer validatesthe transaction within the new data block 630 by checking to make surethat the read set and the write set still match the current world statein the state database 624. Specifically, the committing peer candetermine whether the read data that existed when the endorserssimulated the transaction is identical to the current world state in thestate database 624. When the committing peer validates the transaction,the transaction is written to the blockchain 622 on the distributedledger 620, and the state database 624 is updated with the write datafrom the read-write set. If a transaction fails, that is, if thecommitting peer finds that the read-write set does not match the currentworld state in the state database 724, the transaction ordered into ablock will still be included in that block, but it will be marked asinvalid, and the state database 624 will not be updated.

Referring to FIG. 6B, a new data block 630 (also referred to as a datablock) that is stored on the blockchain 622 of the distributed ledger620 may include multiple data segments such as a block header 640, blockdata 650, and block metadata 660. It should be appreciated that thevarious depicted blocks and their contents, such as new data block 630and its contents. shown in FIG. 6B are merely examples and are not meantto limit the scope of the example embodiments. The new data block 630may store transactional information of N transaction(s) (e.g., 1, 10,100, 500, 1000, 2000, 3000, etc.) within the block data 650. The newdata block 630 may also include a link to a previous block (e.g., on theblockchain 622 in FIG. 6A) within the block header 640. In particular,the block header 640 may include a hash of a previous block's header.The block header 640 may also include a unique block number, a hash ofthe block data 650 of the new data block 630, and the like. The blocknumber of the new data block 630 may be unique and assigned in variousorders, such as an incremental/sequential order starting from zero.

The block data 650 may store transactional information of eachtransaction that is recorded within the new data block 630. For example,the transaction data may include one or more of a type of thetransaction, a version, a timestamp, a channel ID of the distributedledger 620, a transaction ID, an epoch, a payload visibility, achaincode path (deploy tx), a chaincode name, a chaincode version, input(chaincode and functions), a client (creator) identify such as a publickey and certificate, a signature of the client, identities of endorsers,endorser signatures, a proposal hash, chaincode events, response status,namespace, a read set (list of key and version read by the transaction,etc.), a write set (list of key and value, etc.), a start key, an endkey, a list of keys, a Merkel tree query summary, and the like. Thetransaction data may be stored for each of the N transactions.

In some embodiments, the block data 650 may also store new data 662which adds additional information to the hash-linked chain of blocks inthe blockchain 622. The additional information includes one or more ofthe steps, features, processes and/or actions described or depictedherein. Accordingly, the new data 662 can be stored in an immutable logof blocks on the distributed ledger 620. Some of the benefits of storingsuch new data 662 are reflected in the various embodiments disclosed anddepicted herein. Although in FIG. 6B the new data 662 is depicted in theblock data 650 but could also be located in the block header 640 or theblock metadata 660.

The block metadata 660 may store multiple fields of metadata (e.g., as abyte array, etc.). Metadata fields may include signature on blockcreation, a reference to a last configuration block, a transactionfilter identifying valid and invalid transactions within the block, lastoffset persisted of an ordering service that ordered the block, and thelike. The signature, the last configuration block, and the orderermetadata may be added by the ordering service 610. Meanwhile, acommitter of the block (such as blockchain node 612) may addvalidity/invalidity information based on an endorsement policy,verification of read/write sets, and the like. The transaction filtermay include a byte array of a size equal to the number of transactionsin the block data 650 and a validation code identifying whether atransaction was valid/invalid.

FIG. 6C illustrates an embodiment of a blockchain 670 for digitalcontent in accordance with the embodiments described herein. The digitalcontent may include one or more files and associated information. Thefiles may include media, images, video, audio, text, links, graphics,animations, web pages, documents, or other forms of digital content. Theimmutable, append-only aspects of the blockchain serve as a safeguard toprotect the integrity, validity, and authenticity of the digitalcontent, making it suitable use in legal proceedings where admissibilityrules apply or other settings where evidence is taken in toconsideration or where the presentation and use of digital informationis otherwise of interest. In this case, the digital content may bereferred to as digital evidence.

The blockchain may be formed in various ways. In one embodiment, thedigital content may be included in and accessed from the blockchainitself. For example, each block of the blockchain may store a hash valueof reference information (e.g., header, value, etc.) along theassociated digital content. The hash value and associated digitalcontent may then be encrypted together. Thus, the digital content ofeach block may be accessed by decrypting each block in the blockchain,and the hash value of each block may be used as a basis to reference aprevious block. This may be illustrated as follows:

Block 1 Block 2 . . . Block N Hash Value 1 Hash Value 2 Hash Value NDigital Content 1 Digital Content 2 Digital Content N

In one embodiment, the digital content may be not included in theblockchain. For example, the blockchain may store the encrypted hashesof the content of each block without any of the digital content. Thedigital content may be stored in another storage area or memory addressin association with the hash value of the original file. The otherstorage area may be the same storage device used to store the blockchainor may be a different storage area or even a separate relationaldatabase. The digital content of each block may be referenced oraccessed by obtaining or querying the hash value of a block of interestand then looking up that has value in the storage area, which is storedin correspondence with the actual digital content. This operation may beperformed, for example, a database gatekeeper. This may be illustratedas follows:

Blockchain Storage Area Block 1 Hash Value Block 1 Hash Value . . .Content . . . . . . Block N Hash Value Block N Hash Value . . . Content

In the example embodiment of FIG. 6C, the blockchain 670 includes anumber of blocks 678 ₁, 678 ₂, . . . 678 _(N) cryptographically linkedin an ordered sequence, where N≥1. The encryption used to link theblocks 678 ₁, 678 ₂, . . . 678 _(N) may be any of a number of keyed orun-keyed Hash functions. In one embodiment, the blocks 678 ₁, 678 ₂, . .. 678 _(N) are subject to a hash function which produces n-bitalphanumeric outputs (where n is 256 or another number) from inputs thatare based on information in the blocks. Examples of such a hash functioninclude, but are not limited to, a SHA-type (SHA stands for Secured HashAlgorithm) algorithm, Merkle-Damgard algorithm, HAIFA algorithm,Merkle-tree algorithm, nonce-based algorithm, and anon-collision-resistant PRF algorithm. In another embodiment, the blocks678 ₁, 678 ₂, . . . , 678 _(N) may be cryptographically linked by afunction that is different from a hash function. For purposes ofillustration, the following description is made with reference to a hashfunction, e.g., SHA-2.

Each of the blocks 678 ₁, 678 ₂, . . . , 678 _(N) in the blockchainincludes a header, a version of the file, and a value. The header andthe value are different for each block as a result of hashing in theblockchain. In one embodiment, the value may be included in the header.As described in greater detail below, the version of the file may be theoriginal file or a different version of the original file.

The first block 678 ₁ in the blockchain is referred to as the genesisblock and includes the header 672 ₁, original file 674 ₁, and an initialvalue 676 ₁. The hashing scheme used for the genesis block, and indeedin all subsequent blocks, may vary. For example, all the information inthe first block 678 ₁ may be hashed together and at one time, or each ora portion of the information in the first block 678 ₁ may be separatelyhashed and then a hash of the separately hashed portions may beperformed.

The header 672 ₁ may include one or more initial parameters, which, forexample, may include a version number, timestamp, nonce, rootinformation, difficulty level, consensus protocol, duration, mediaformat, source, descriptive keywords, and/or other informationassociated with original file 674 ₁ and/or the blockchain. The header672 ₁ may be generated automatically (e.g., by blockchain networkmanaging software) or manually by a blockchain participant. Unlike theheader in other blocks 678 ₂ to 678 _(N) in the blockchain, the header672 ₁ in the genesis block does not reference a previous block, simplybecause there is no previous block.

The original file 674 ₁ in the genesis block may be, for example, dataas captured by a device with or without processing prior to itsinclusion in the blockchain. The original file 674 ₁ is received throughthe interface of the system from the device, media source, or node. Theoriginal file 674 ₁ is associated with metadata, which, for example, maybe generated by a user, the device, and/or the system processor, eithermanually or automatically. The metadata may be included in the firstblock 678 ₁ in association with the original file 674 ₁.

The value 676 ₁ in the genesis block is an initial value generated basedon one or more unique attributes of the original file 674 ₁. In oneembodiment, the one or more unique attributes may include the hash valuefor the original file 674 ₁, metadata for the original file 674 ₁, andother information associated with the file. In one implementation, theinitial value 676 ₁ may be based on the following unique attributes:

-   -   1) SHA-2 computed hash value for the original file    -   2) originating device ID    -   3) starting timestamp for the original file    -   4) initial storage location of the original file    -   5) blockchain network member ID for software to currently        control the original file and associated metadata

The other blocks 678 ₂ to 678 _(N) in the blockchain also have headers,files, and values. However, unlike the first block 672 _(i), each of theheaders 672 ₂ to 672 _(N) in the other blocks includes the hash value ofan immediately preceding block. The hash value of the immediatelypreceding block may be just the hash of the header of the previous blockor may be the hash value of the entire previous block. By including thehash value of a preceding block in each of the remaining blocks, a tracecan be performed from the Nth block back to the genesis block (and theassociated original file) on a block-by-block basis, as indicated byarrows 680, to establish an auditable and immutable chain-of-custody.

Each of the header 672 ₂ to 672 _(N) in the other blocks may alsoinclude other information, e.g., version number, timestamp, nonce, rootinformation, difficulty level, consensus protocol, and/or otherparameters or information associated with the corresponding files and/orthe blockchain in general.

The files 674 ₂ to 674 _(N) in the other blocks may be equal to theoriginal file or may be a modified version of the original file in thegenesis block depending, for example, on the type of processingperformed. The type of processing performed may vary from block toblock. The processing may involve, for example, any modification of afile in a preceding block, such as redacting information or otherwisechanging the content of, taking information away from, or adding orappending information to the files.

Additionally, or alternatively, the processing may involve merelycopying the file from a preceding block, changing a storage location ofthe file, analyzing the file from one or more preceding blocks, movingthe file from one storage or memory location to another, or performingaction relative to the file of the blockchain and/or its associatedmetadata. Processing which involves analyzing a file may include, forexample, appending, including, or otherwise associating variousanalytics, statistics, or other information associated with the file.

The values in each of the other blocks 676 ₂ to 676 _(N) in the otherblocks are unique values and are all different as a result of theprocessing performed. For example, the value in any one blockcorresponds to an updated version of the value in the previous block.The update is reflected in the hash of the block to which the value isassigned. The values of the blocks therefore provide an indication ofwhat processing was performed in the blocks and also permit a tracingthrough the blockchain back to the original file. This tracking confirmsthe chain-of-custody of the file throughout the entire blockchain.

For example, consider the case where portions of the file in a previousblock are redacted, blocked out, or pixilated in order to protect theidentity of a person shown in the file. In this case, the blockincluding the redacted file will include metadata associated with theredacted file, e.g., how the redaction was performed, who performed theredaction, timestamps where the redaction(s) occurred, etc. The metadatamay be hashed to form the value. Because the metadata for the block isdifferent from the information that was hashed to form the value in theprevious block, the values are different from one another and may berecovered when decrypted.

In one embodiment, the value of a previous block may be updated (e.g., anew hash value computed) to form the value of a current block when anyone or more of the following occurs. The new hash value may be computedby hashing all or a portion of the information noted below, in thisexample embodiment.

-   -   a) new SHA-2 computed hash value if the file has been processed        in any way (e.g., if the file was redacted, copied, altered,        accessed, or some other action was taken)    -   b) new storage location for the file    -   c) new metadata identified associated with the file    -   d) transfer of access or control of the file from one blockchain        participant to another blockchain participant

FIG. 6D illustrates an embodiment of a block which may represent thestructure of the blocks in the blockchain 690 in accordance with oneembodiment. The block, Block_(i), includes a header 672 _(i), a file 674_(i), and a value 676 _(i).

The header 672 _(i) includes a hash value of a previous block Block_(i)and additional reference information, which, for example, may be any ofthe types of information (e.g., header information including references,characteristics, parameters, etc.) discussed herein. All blocksreference the hash of a previous block except, of course, the genesisblock. The hash value of the previous block may be just a hash of theheader in the previous block or a hash of all or a portion of theinformation in the previous block, including the file and metadata.

The file 6′74i includes a plurality of data, such as Data 1, Data 2, . .. , Data N in sequence. The data are tagged with metadata Metadata 1,Metadata 2, . . . , Metadata N which describe the content and/orcharacteristics associated with the data. For example, the metadata foreach data may include information to indicate a timestamp for the data,process the data, keywords indicating the persons or other contentdepicted in the data, and/or other features that may be helpful toestablish the validity and content of the file as a whole, andparticularly its use a digital evidence, for example, as described inconnection with an embodiment discussed below. In addition to themetadata, each data may be tagged with reference REF₃, REF₂, REF_(N) toa previous data to prevent tampering, gaps in the file, and sequentialreference through the file.

Once the metadata is assigned to the data (e.g., through a smartcontract), the metadata cannot be altered without the hash changing,which can easily be identified for invalidation. The metadata, thus,creates a data log of information that may be accessed for use byparticipants in the blockchain.

The value 676 _(i) is a hash value or other value computed based on anyof the types of information previously discussed. For example, for anygiven block Block_(i), the value for that block may be updated toreflect the processing that was performed for that block, e.g., new hashvalue, new storage location, new metadata for the associated file,transfer of control or access, identifier, or other action orinformation to be added. Although the value in each block is shown to beseparate from the metadata for the data of the file and header, thevalue may be based, in part or whole, on this metadata in anotherembodiment.

Once the blockchain 670 is formed, at any point in time, the immutablechain-of-custody for the file may be obtained by querying the blockchainfor the transaction history of the values across the blocks. This query,or tracking procedure, may begin with decrypting the value of the blockthat is most currently included (e.g., the last (N^(th)) block), andthen continuing to decrypt the value of the other blocks until thegenesis block is reached and the original file is recovered. Thedecryption may involve decrypting the headers and files and associatedmetadata at each block, as well.

Decryption is performed based on the type of encryption that took placein each block. This may involve the use of private keys, public keys, ora public key-private key pair. For example, when asymmetric encryptionis used, blockchain participants or a processor in the network maygenerate a public key and private key pair using a predeterminedalgorithm. The public key and private key are associated with each otherthrough some mathematical relationship. The public key may bedistributed publicly to serve as an address to receive messages fromother users, e.g., an IP address or home address. The private key iskept secret and used to digitally sign messages sent to other blockchainparticipants. The signature is included in the message so that therecipient can verify using the public key of the sender. This way, therecipient can be sure that only the sender could have sent this message.

Generating a key pair may be analogous to creating an account on theblockchain, but without having to actually register anywhere. Also,every transaction that is executed on the blockchain is digitally signedby the sender using their private key. This signature ensures that onlythe owner of the account can track and process (if within the scope ofpermission determined by a smart contract) the file of the blockchain.

FIG. 7 illustrates an example system 700 that supports one or more ofthe example embodiments described and/or depicted herein. The system 700comprises a computer system/server 702, which is operational withnumerous other general purpose or special purpose computing systemenvironments or configurations. Examples of well-known computingsystems, environments, and/or configurations that may be suitable foruse with computer system/server 702 include, but are not limited to,personal computer systems, server computer systems, thin clients, thickclients, hand-held or laptop devices, multiprocessor systems,microprocessor-based systems, set top boxes, programmable consumerelectronics, network PCs, minicomputer systems, mainframe computersystems, and distributed cloud computing environments that include anyof the above systems or devices, and the like.

Computer system/server 702 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 702 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 7, computer system/server 702 in cloud computing node700 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 702 may include, but are notlimited to, one or more processors or processing units 704, a systemmemory 706, and a bus that couples various system components includingsystem memory 706 to processor 704.

The bus represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Computer system/server 702 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 702, and it includes both volatileand non-volatile media, removable and non-removable media. System memory706, in one embodiment, implements the flow diagrams of the otherfigures. The system memory 706 can include computer system readablemedia in the form of volatile memory, such as random-access memory (RAM)710 and/or cache memory 712. Computer system/server 702 may furtherinclude other removable/non-removable, volatile/non-volatile computersystem storage media. By way of example only, storage system 714 can beprovided for reading from and writing to a non-removable, non-volatilemagnetic media (not shown and typically called a “hard drive”). Althoughnot shown, a magnetic disk drive for reading from and writing to aremovable, non-volatile magnetic disk (e.g., a “floppy disk”), and anoptical disk drive for reading from or writing to a removable,non-volatile optical disk such as a CD-ROM, DVD-ROM or other opticalmedia can be provided. In such instances, each can be connected to thebus by one or more data media interfaces. As will be further depictedand described below, memory 706 may include at least one program producthaving a set (e.g., at least one) of program modules that are configuredto carry out the functions of various embodiments of the application.

Program/utility 716, having a set (at least one) of program modules 718,may be stored in memory 706 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 718 generally carry out the functionsand/or methodologies of various embodiments of the application asdescribed herein.

As will be appreciated by one skilled in the art, aspects of the presentapplication may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present application may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present application may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Computer system/server 702 may also communicate with one or moreexternal devices 720 such as a keyboard, a pointing device, a display722, etc.; one or more devices that enable a user to interact withcomputer system/server 702; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 702 to communicate withone or more other computing devices. Such communication can occur viaI/O interfaces 724. Still yet, computer system/server 702 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 726. As depicted, network adapter 726communicates with the other components of computer system/server 702 viaa bus. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 702. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

Although an exemplary embodiment of at least one of a system, method,and non-transitory computer readable medium has been illustrated in theaccompanied drawings and described in the foregoing detaileddescription, it will be understood that the application is not limitedto the embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions as set forth and defined by thefollowing claims. For example, the capabilities of the system of thevarious figures can be performed by one or more of the modules orcomponents described herein or in a distributed architecture and mayinclude a transmitter, receiver or pair of both. For example, all orpart of the functionality performed by the individual modules, may beperformed by one or more of these modules. Further, the functionalitydescribed herein may be performed at various times and in relation tovarious events, internal or external to the modules or components. Also,the information sent between various modules can be sent between themodules via at least one of: a data network, the Internet, a voicenetwork, an Internet Protocol network, a wireless device, a wired deviceand/or via plurality of protocols. Also, the messages sent or receivedby any of the modules may be sent or received directly and/or via one ormore of the other modules.

One skilled in the art will appreciate that a “system” could be embodiedas a personal computer, a server, a console, a personal digitalassistant (PDA), a cell phone, a tablet computing device, a smartphoneor any other suitable computing device, or combination of devices.Presenting the above-described functions as being performed by a“system” is not intended to limit the scope of the present applicationin any way but is intended to provide one example of many embodiments.Indeed, methods, systems and apparatuses disclosed herein may beimplemented in localized and distributed forms consistent with computingtechnology.

It should be noted that some of the system features described in thisspecification have been presented as modules, in order to moreparticularly emphasize their implementation independence. For example, amodule may be implemented as a hardware circuit comprising custom verylarge-scale integration (VLSI) circuits or gate arrays, off-the-shelfsemiconductors such as logic chips, transistors, or other discretecomponents. A module may also be implemented in programmable hardwaredevices such as field programmable gate arrays, programmable arraylogic, programmable logic devices, graphics processing units, or thelike.

A module may also be at least partially implemented in software forexecution by various types of processors. An identified unit ofexecutable code may, for instance, comprise one or more physical orlogical blocks of computer instructions that may, for instance, beorganized as an object, procedure, or function. Nevertheless, theexecutables of an identified module need not be physically locatedtogether but may comprise disparate instructions stored in differentlocations which, when joined logically together, comprise the module andachieve the stated purpose for the module. Further, modules may bestored on a computer-readable medium, which may be, for instance, a harddisk drive, flash device, random access memory (RAM), tape, or any othersuch medium used to store data.

Indeed, a module of executable code could be a single instruction, ormany instructions, and may even be distributed over several differentcode segments, among different programs, and across several memorydevices. Similarly, operational data may be identified and illustratedherein within modules and may be embodied in any suitable form andorganized within any suitable type of data structure. The operationaldata may be collected as a single data set or may be distributed overdifferent locations including over different storage devices, and mayexist, at least partially, merely as electronic signals on a system ornetwork.

It will be readily understood that the components of the application, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations.Thus, the detailed description of the embodiments is not intended tolimit the scope of the application as claimed but is merelyrepresentative of selected embodiments of the application.

One having ordinary skill in the art will readily understand that theabove may be practiced with steps in a different order, and/or withhardware elements in configurations that are different than those whichare disclosed. Therefore, although the application has been describedbased upon these preferred embodiments, it would be apparent to those ofskill in the art that certain modifications, variations, and alternativeconstructions would be apparent.

While preferred embodiments of the present application have beendescribed, it is to be understood that the embodiments described areillustrative only and the scope of the application is to be definedsolely by the appended claims when considered with a full range ofequivalents and modifications (e.g., protocols, hardware devices,software platforms etc.) thereto.

What is claimed is:
 1. A system, comprising: a processor of a document server; a memory on which are stored machine readable instructions that when executed by the processor, cause the processor to: split a document provided by a document owner node into a plurality of segments to be stored on a ledger of a blockchain; detect a change to the document made by an authorized participant node; update a segment of the plurality of segments stored on the ledger based on the change to the document; collect votes on the change to the document from a plurality of participant nodes; and commit the updated segment to the blockchain based on the votes.
 2. The system of claim 1, wherein the instructions further cause the processor to send a notification of the change to the document to a set of participant nodes of the plurality of the participant nodes authorized to view the document.
 3. The system of claim 1, wherein the instructions further cause the processor to determine view and edit access for each of the segments of the document for the plurality of the participant nodes.
 4. The system of claim 1, wherein the instructions further cause the processor to receive instructions from the document owner on a consensus method for reconciliation of changes of the document.
 5. The system of claim 1, wherein the instructions further cause the processor to assign participant nodes selected by the document owner from the plurality of the participant nodes to vote on the document change.
 6. The system of claim 5, wherein the instructions further cause the processor to record a ledger entry on the blockchain if a consensus on the document change is not reached by the participant nodes assigned to vote.
 7. The system of claim 1, wherein the instructions further cause the processor to execute a smart contract to restrict access to the segments of the document identified by the document owner.
 8. A method, comprising: splitting, by a document server, a document provided by a document owner node into a plurality of segments to be stored on a ledger of a blockchain; detecting, by the document server, a change to the document made by an authorized participant node; updating, by the document server, a segment of the plurality of segments stored on the ledger based on the change to the document; collecting, by the document server, votes on the change to the document from a plurality of participant nodes; and committing the updated segment to the blockchain based on the votes.
 9. The method of claim 8, further comprising sending a notification of the change to the document to a set of participant nodes of the plurality of the participant nodes authorized to view the document.
 10. The method of claim 8, further comprising determining view and edit access for each of the segments of the document for the plurality of the participant nodes.
 11. The method of claim 8, further comprising receiving instructions from the document owner on a consensus method for reconciliation of changes of the document.
 12. The method of claim 8, further comprising assigning participant nodes selected by the document owner from the plurality of the participant nodes to vote on the document change.
 13. The method of claim 12, further comprising recording a ledger entry on the blockchain if a consensus on the document change is not reached by the participant nodes assigned to vote.
 14. The method of claim 8, further comprising executing a smart contract to restrict access to the segments of the document identified by the document owner.
 15. A non-transitory computer readable medium comprising instructions, that when read by a processor, cause the processor to perform: splitting a document provided by a document owner node into a plurality of segments to be stored on a ledger of a blockchain; detecting a change to the document made by an authorized participant node; updating a segment of the plurality of segments stored on the ledger based on the change to the document; collecting votes on the change to the document from a plurality of participant nodes; and committing the updated segment to the blockchain based on the votes.
 16. The non-transitory computer readable medium of claim 15, further comprising instructions, that when read by the processor, cause the processor to send a notification of the change to the document to a set of participant nodes of the plurality of the participant nodes authorized to view the document.
 17. The non-transitory computer readable medium of claim 15, further comprising instructions, that when read by the processor, cause the processor to determine view and edit access for each of the segments of the document for the plurality of the participant nodes.
 18. The non-transitory computer readable medium of claim 15, further comprising instructions, that when read by the processor, cause the processor to receive instructions from the document owner on a consensus method for reconciliation of changes of the document.
 19. The non-transitory computer readable medium of claim 15, further comprising instructions, that when read by the processor, cause the processor to assign participant nodes selected by the document owner from the plurality of the participant nodes to vote on the document change.
 20. The non-transitory computer readable medium of claim 19, further comprising instructions, that when read by the processor, cause the processor to record a ledger entry on the blockchain if a consensus on the document change is not reached by the participant nodes assigned to vote. 